Fibrosis control using cyclooxygenase 2 inhibitor in ligamentum flavum

김태환 Graduate School, Yonsei University 2018 국내박사

Cyclooxygenase (COX) is a rate-limiting enzyme in inflammatory cascades, and inhibition of cyclooxygenase has been shown to prevent inflammation and fibrosis in various organs. We hypothesized that COX-2 inhibitor might also have an antifibrotic effect in hypertrophied ligamentum flavum (LF) and tried to find out the mechanism of the antifibrotic effect of a COX-2 inhibitor. LF tissue was obtained from 5 patients (age range, 49-65 years old) during surgery for lumbar spinal stenosis. To confirm the antifibrotic effect of a COX-2 inhibitor on LF, the total collagen content was compared between LF samples with and without the COX-2 inhibitor. Western blots were performed to find out the possible mechanism of the antifibrotic effect of the COX-2 inhibitor. In this study, the COX-2 inhibitor significantly reduced PGE2 in LF cells (p<0.001), and also reduced the total collagen content (p=0.043). The expression of phosphorylated p38 (p=0.017), phosphorylated ERK (p=0.025), and MMP-13 (p<0.001) significantly decreased with administration of the COX-2 inhibitor. The expressions of p65, MMP-1,2 and TIMP-1,2 were not changed with the administration of the COX-2 inhibitor. Our study demonstrates that the COX-2 inhibitor suppresses the LF fibrosis in vitro and suggests that the antifibrotic effect of the COX-2 inhibitor on LF is closely related with the MAPK pathway including p38 and ERK. Cyclooxygenase (COX)는 염증반응에 있어 속도 조절 효소로서, 억제제 투여시 다양한 기관에서 염증과 섬유화를 막는 효과를 거두는 것으로 알려져 있다. 본 연구에서는 선택적 COX-2 억제제가 비후된 황색인대에서도 섬유화를 억제할 것이라 가정하고, 이와 관련된 기전을 찾고자 하였다. 척추관 협착증으로 수술을 시행한 5명의 환자로부터 수술 중 황색인대를 채취하였다 (나이, 49~65세). 황색인대 세포에 COX-2 억제제를 투여한 군과 그렇지 않은 군 사이에 콜라겐의 총 용량을 비교하여 항섬유효과를 확인하였고, western blot을 이용하여 COX-2억제제에 의한 항섬유작용의 기전을 밝히고자 하였다. COX-2 억제제는 황색인대 세포에서 PGE2 (p<0.001) 및 콜라겐의 총량을 (p=0.043) 의미있게 감소시켰다. Western blot 상에서 phosphorylated p38 (p=0.017), phosphorylated ERK (p=0.025), MMP-13 (p<0.001)은 COX-2 억제제의 투여 후 황색인대에서의 발현이 의미있게 감소하였으나, p65, MMP-1,2 및 TIMP-1,2는 COX-2 억제제 투여로 인한 의미있는 변화를 보이지 않았다. 본 연구에서 COX-2 억제제는 황색인대의 섬유화를 억제하였고, 이러한 항섬유작용은 p38 및 ERK를 포함한 MAPK 경로의 억제와 연관된 것으로 나타났다.

Mobilsation des reser ves azotees et contribution de l' azote du milieu a la repousse de medicago sativa l. apres une coupe

Kim, Tae-Hwan Universite de Caen 1992 해외박사

(An)Empirical study of the factors contributing to rapid church g rowth in Korea

Kim, Tae Hwan Eastern Baptist Theological Seminary 1984 국내박사

Untersuchung der Zitronensaeureproduktion im Hubstrahlreaktor

Hwan, Kim, Tae Technischen Universitaet Berlin 1987 국내박사

Biologische anaerobe Abwasserreinigung und Biogaserzeugung im Einstufigen Hubstrahlreaktor

Hwan, Kim, Tae Technischen Universitaet Berlin 1984 국내박사

CULTURAL DIFFERENCES IN PERCEPTION ON INTERNET SHOPPING : A MULTI-VARIABLE STUDY IN THE UNITED STATES AND KOREA

Kim, Tae Hwan Mississippi State University 2002 해외박사

Over the past decade, Internet shopping has grown substantially. Although the fast advancing information infrastructure makes the connectivity possible to reach almost anywhere in the world, it does not necessarily ensure a successful development of Internet shopping platform for every country. An important factor that could influence the diffusion of Internet commerce is the difference in cultural background of each market group. To examine the effect of cultural differences on the perception for Internet shopping, Internet shoppers from two markedly different countries in their cultural background ? U.S. and Korea - were chosen, and the perception for Internet shopping of U.S. Internet shoppers is contrasted with those of Korean shoppers. Using the variables identified by the literature, this study identified differences in perception on Internet shopping between U.S. and Korean shoppers and also identified the particular variables that facilitate or hinder the Internet shoppers in each country. In order to reach a proper subset of Internet shoppers, more than 100 experienced and inexperienced Internet shoppers in the U.S. and Korea were chosen. For the analysis of data, multivariate analysis of variance (MANOVA), analysis of variance (ANOVA), and factor analysis were utilized. The results indicate that the perception of Internet shoppers in the two countries is different in most of the variables identified in this study.

Field-free magnetization switching and induced exchange bias by spin torque in Co0.7-Ni0.3-O-Pt phase alloy single layer

Tae-Hwan Kim 대구경북과학기술원 대학원 2021 국내석사

The spin Hall effect has been attracting worldwide attention as one of the methods for controlling the magnetic spin structure. However, it has the limitations in layered structure and requirement of high current density, Jc ~ 10^10A/m2. In this thesis, the Co0.7-Ni0.3-O-Pt phase alloy single layer having a structure in which each phase is randomly distributed in several nanometer sizes like the alloy was reported. Unlike general layered thin film system, this structure has a unique interfacial structure as Co, Ni, O and Pt phases are randomly distributed in a single layer. When a current is applied to this thin film, the spin Hall effect generated by the current flowing through the Pt phases applies spin torque to other phases at the interface, and this result was observed through the change of the exchange bias. To find out the cause of the occurrence, the same structure was fabricated using Au instead of Pt and Fe instead of Co and Ni, and the same experiment was performed. As a result, it was found that the spin structure of the antiferromagnetic material was controlled by the spin Hall effect. In addition, the magnitude of the induced exchange bias was proportional to the current density and degree of oxidation of the film and exhibited stable reversibility and repeatability within the measured current density range. Using this, field-free magnetization switching was also performed and all of the results were achieved at a current density of Jc ~10^10A/m2, which is one order lower than the previously reported value. Therefore, the results of this thesis overcome the limitations of the spin torque and the layered thin film system through phase alloy single layer structure, which suggests the possibility of improving the performance of a device designed based on the control of the spin structure.

High frequency signal transmission characteristics of helical pigtail structure

김태환 Graduate School, Yonsei University 2019 국내석사

The pigtail structure in coaxial cable is a typical termination structure used when non-uniform grounding is required. Pigtail terminations have been used frequently because they are easy to make and cost less, but they have limitations that can only be used at low frequencies due to impedance mismatch between the cable and the pigtail. In this study, improvement of signal transmission characteristics at high frequencies in the pigtail structure was investigated. The pigtail structure can be analyzed using dipole antenna and transmission line theory, and common mode radiation and impedance can be obtained. In this thesis, two kinds of theories are used for analysis, and two parallel wires are substituted for the equivalent circuit to derive the impedance. Finally, a structure called a helical pigtail has been proposed by providing a structural change for improved signal transmission characteristics. A total of four models is presented according to the number of pigtails and the application of helical structure, and the reliability of each experimental result is derived. In the two models with one pigtail, the values of -6.5dB and -4dB, respectively, were found to improve the signal transmission characteristics of the helical structure, and in the two models with two pigtails, we confirmed that the values of -5dB and -2dB have improved the helical structure. The signal transmission characteristics were compared with the existing pigtail structure, and the Time-Domain Reflectometer (TDR) was measured to confirm that the helical pigtail structure has better signal transmission characteristics due to low impedance mismatch.

Novel and physiologically relevant population pharmacokinetic in vitro-in vivo correlation modeling approaches for the development of sustained release dosage forms

Kim, Taehwan Sungkyunkwan University 2015 국내박사

Validity of occurrence of randomness and discovery of aptitude in man : KOMA consolidated job performance psychological ability test, KOMA aptitude psychology test for driving, KOMA precognition ability test of industrial safety

김태환 Central State University 1998 해외박사

본인(김태환)은 1981년 일본의 쥬꾜(中京)대학 재학시절부터 산업 심리검사의 기초 연구를 통하여 보다 신뢰성과 타당성이 높은 심리검사를 연구하던 중 지도교수의 도움으로 난수검사(0∼9까지의 숫자를 최대한 불규칙하고 빠르게 일정한 시간에 표현함)을 접하게 되었고 그 검사 테크닉을 근간으로 우찌다 크레페링 검사와의 상관분석을 통하여 난수검사가 인간의 심리측정분석의 가능성을 발견하게 되었다. 난수검사의 학문적 이론을 보다 깊이 연구하기 위하여 니혼(日本)대학 대학원의 박사과정에서 문헌연구와 응용을 병행하였다. 석사논문으로는 인간 난수검사의 특성을 연구를 통하여 산업사회에 적용과 과학적 입증을 논하였다. 그리고 그 연구 결과를 근간으로 심리검사를 제작하기 시작하여 현재 KOMA직무능력검사, KOMA운전적성심리검사, KOMA산업안전예지능력검사외 69종류를 완성하여 한국의 관공서, 기업체, 학교, 연구기관, 기타에서 약10년동안 약 10만 여명에게 실시하여 인재개발적 측면에서 그 공헌도가 크다고 본다. 학문적 연구와 결과를 한양대학교 교육대학원 강사, 중앙대학교 건설대학원 객원교수, 조선대학교 협동교수로서 강의를 통하여 많은 제자 양성에도 노력한 나머지 한국 사회에 심리검사의 저변확대에도 공헌하였다. 해서, 본인은 지금까지의 심리검사 연구를 하여 한국사회에 실제로 사용하고있는 72가지중 3가지 검사(KOMA직무능력검사, KOMA운전적성심리검사, KOMA산업안전예지능력검사)를 정리하여 박사학위 논문으로 제출한다.